Belfast Harbour’s D1 Offshore Wind Turbine Logistics Facility

The D1 Project at Belfast Harbour, the UK’s first purpose-built offshore wind logistics facility, involved constructing a 500m-long quay structure and a deep-water berth. This extensive project included dredging and disposing of 600,000m³ of material and placing 150,000 tonnes of rock armour protection for the new quay. As the largest contract ever undertaken in Belfast Harbour’s 400-year history, it also required developing 50 acres of hinterland. Remarkably, the works were completed in just over a year.

Ayesa played a crucial role in this project by designing the permanent anchors for the combi-wall, which comprised 32m-long, 1.6m diameter tubular piles combined with 22m-long sheet piles. The anchors involved rock anchors inserted into 367No 30m-long, 760mm diameter raking piles, tied back to a reinforced concrete anchor beam. Additionally, Ayesa acted as the temporary works designer and provided geotechnical advice for the value engineering of the heavy-duty hinterland pavement and support piling.

Leveraging our multidisciplinary expertise, we provided significant value to the project by integrating our construction stage knowledge of quay walls with our landside geotechnical remediation experience. We critically reviewed the client’s existing concept design and recommended innovative variations, such as using a geosynthetic ground stabilisation solution. This approach dramatically reduced the reliance on standard piling techniques, resulting in a shorter programme length and a capital saving of approximately £750,000.